3.4. CTRP9 Alleviates ox-LDL-Induced VSMC-Derived Foam Cell
Necroptosis
To clarify the potential role of CTRP9 in ox-LDL-induced necroptosis of
VSMC-derived macrophage-like foam cells, we examined cell morphology
using electron microscopy. VSMC-derived foam cells were either left
untreated or treated with 10 μg/mL ox-LDL in the presence of different
concentrations of CTRP9. With increasing CTRP9 concentration, the number
of necroptotic cells decreased significantly, and the structure of the
cell membrane and organelles became increasingly complete (Fig. 4a). In
addition to altering cell morphology, CTRP9 reduced the proportion of
PI-positive cells (Fig. 4b). Western blotting analysis revealed that
ox-LDL promoted RIP1 and MLKL phosphorylation in VSMC-derived foam
cells, whereas CTRP9 prevented this phosphorylation, and higher
concentrations of CTRP9 further reduced the expression of
necroptosis-related proteins
(Fig. 4c and d). Thus, CTRP9 effectively protected VSMC-derived foam
cells from ox-LDL-induced necroptosis. To further verify this finding,
we measured the expression levels of cell phenotype markers,
pro-atherosclerotic genes, and inflammatory factors using qRT-PCR and
found that CTRP9 inhibited the expression of pro-atherosclerotic genes
and inflammatory factors induced by ox-LDL in a dose-dependent manner
(Fig. 4e).